Sacramento daily record-union. [volume] (Sacramento [Calif.]) 1875-1891, 1887-06-18
FRUIT PESTS.
THE USE OF EASES AGAINST
SCALE INSECTS.
Interesting Experiments for Extir.
pating the White (Cottony
Cushion Scale-Results.

w nltC tIOttOnV
Cushion Scale-Results.
Some time ago the Agricultural Depart.
ment was requested by A. B. and A. s
Chapman, L. H. Titus and ]. C. Newton
prominent orange-growers of Los Angelo:
county, to consider experiments with the
view of determining the efficacy of certain
gases as insecucides-with special refer.
ence to the white scale, Icer1a parchasi
The following is a summary of results. OF
which full report will be published here.
after
The use of gases for this purpose has
been long contemplated, and various ap-
pliances have been suggested for the ready
application of any eficacious gas. The
ease with which gas penetrates to all parts
of the tree naturally suggests its use as pre-
ferable to washes, which at best leave MANY
parts of the foliage and infested branches
untouched, even when sprayed with the
greatest care. In order that the pas NAV
be an efficient insecticide, it must be So
poisonous that even when applied in small
quantities 1t produces fatal results; for in
the application the air confined in the tent
covering the tree dilutes the gas to great ex-
tent. Again, the gas must be capableof being
generated quickly in sufficient volume,
The record below shows that cnly one of
the gases employed fulfilled these condi-
tons to satisfactory extent Preliminary
experiments with some others having
shown their untitness for the purpose
either on account OF expense or because of
injury to the foliage, or imperfect action on
the insects, their study was not pursued
further.
APPLIANCES PoR APPLICATION.
The tent for covering the tree is made of
heavy ed-ticking, thoroughly oiled with
linseed oil. This cloth serves the purpose
best, as 1t IS very closely woven, is pliable
and easily folded
The support of the tent, devised by Mr..
| Titus, is very ingeniously contriyed scat
folding mounted on wheels, which serve
| to move il from one tree TO another. It's
dimensions are % feet high, with base of
2Ox20 feet. Its upper part is 20x12, and
carries upon the top roller made of gal
| vanized iron (6 inches in diameter and II
feet long, upon which the tent is rolled
when taken from the tree. Side guy-ropes
are attached to the bottom of the tent and
run through pulleys at the upper corners of
the scaffold They are used to open the
tent when II IS to be dropped over the tree.
and to fold 1t up when it is removed. The
nghtness OF the apparatus allows of its
being easily removed by two men. who
operate the whole. If necessary, two or
more tents can be handled by the same
scattolding, one tent being left over a tree
while the scaffolding is moved to the next.
In adjusting the tent the bottom is placed
on the ground about three feet from the
tree and covered with earth. This brings
the gas to bear upon the base of the tree
and the surrounding soil.
The generator in which the gases were
produced consists of a heavy sheet-irOn
cylinder, IL inches in diameter and 10
inches high. The bottom rests on q plank.
and to the top is fitted a movable cover sus-
pended in frame by bench screW. Into
the cover are htted two pieces of gas-pipe-
| one tor the exit of the gas toward the tent.
and the other, connected with a pump. car
RES the gas which returns from the tent.
| TWO small reservoirs are also inserted in
the cover; IN these are contained the solu-
tons which are to flow into the generator
for the production of the gas
In order to establish circulation and to
force the gas into the tent, a pump is used
which also serves to exhaust the gas from
the upper part of the tent, and to force it
again through the generator 1t is proposed
to replace the pump by small fan blower,
which is much more expeditions than the
common pump which was used
THE GASES ExPERIMENrED WITH.
Among the gases used were chlorine
sulphuretted hydrogen, ammonia, carbon
bisulphide, carbon monoxide, carbonie
acid, hydrocyanic acid, and carbolic acid
vaporized by heat.
Chlorine.-Some preliminary experi-
menfS made n small 49,
| which this gas had been introduced Some
infested branches were allowed to remain
IN them for times varying from to 80
minutes, without any noticeable effect be-
ing produced on the insect Atmosphere
more strongly saturated with the gas proved
fatal to the insect in short time In other
treatments, extending over Is hours, with
less saturated atmospberes, only small
percentage of the insects were killed. No
decided effects were noticeable on the
foliage unless the gas was very concen-
trated.
Carbon Bisulphide.-A lime tree, II feet
IN diameter OF top, was treated with the
vapor of y pounds of sulphide of carbon
for 40 minutes. AT the end of this time
the insects were lively, and during the
treatment had crawled up and collected
around rope surrounding the tree, at the
point where the gas was being injected
from the hose. 1t proved that the gas thus
used Injuries neither the insects nor the
foliage. 1t is upon record, however, that
In cases where the vapor has not been thor
oughly ditfused, but was allowed to flow
down from an open vessel placed in the
top of the tent, serious injury was done to
the foliage at points where the undiiuted
vapor flowed down.
Sulphuretted Hydrogen.-Seyeral treat
ments with this gas were made on a small
| scale the annlipafInr laStinO = 10
minutes. The effects produced either with
diluted or concentrated gas were similar to
those produced by chlorine except that
even the concentrated sulphuretted hydro
gen did not ininriously affect the foliage
An experiment in which whole tree was
treated in the tent for 10 minutes, with
quite concentrated sulphuretted gas,
ishowed clearly that the effect was far from
being satisfactory the insects for the mo-
an hour and a half the majority of them
were again moving about
, Ammonia vapOr from one pound
and half of strong ammonia water was
applied to an 1l-foot lime tree for 30 min
utes. The results were disastrous to the
foliage; the leaves were all scalded, and in
few days all dropped from the tree, and
even the newer growth of wood was in
jured. The insects, however, were not per-
| OSPNiOAl
Carbon Monoxide.-Very strong hopes
have been entertained by many for the sue
cessful application of this gas. Its appa-
rent cheapness and easy production, when
the necessary plant is once erected, would
recommend it. Unfortunately our expert
ments show that it is not sufficiently eff
fectiye to warrant its use. The gas was OBJ
tanned by forcing air through small fur
mace filled with red-hot charcoal, care being
taken to cool and to measure the gas before
applying it. No appreciate effect was
noticeable after forty minutes. In dupli-
cate experiment, in which the charcoal
was more strongly ignited and continuously
introduced into the barrel for thirty min
utes, only slightly better results were OBJ
tanned.
( Oxalic Acid-It was thought that the
production of carbon monoxide by decom-
position of oxalic acid by heat might be
substituted for the previous method of gen.
Grating this gas. 0ne-quarter of pound
of oxalic was ignited, and the gases applied
in manner similar to that of the preced-
ing experiment. Neither the insects nor
the foliage were harmed in the least. This
experiment has incidentally shown that
| the vaOor Of ff1rraic and oyaIic acids al.,